I've never seen this myself, and have not read of its happening to anyone else. We'll be watching to see if someone else reports it.
Any time something happens that shouldn't, this is what the engineers need to know, in order to track down the problem, besides what happened:
Could you reproduce it, or make it happen again?
What steps did you take to reproduce it?
Your OS and browser (ex., Windows 7 and Firefox 10)
The url of the error
Any other info you think may help